Sophia Bush acted opposite Hilarie Burton and Bethany Joy Lenz for years on their series "One Tree Hill," but reuniting with them on screen a decade after the series finale on her CBS medical drama " Good Sam " caught her off guard.

"I would catch myself in rehearsals, just staring at them and then going, 'Oh, God. I have a line. I have to do my job.'"

Bush described the experience as "so comfortable and also wild. We've done it so many times together, but we're all playing such different women."

On the March 23 episode, Lenz and Burton play sisters Gretchen and Amy Taylor. They encounter Bush's Dr. Sam Griffith when Amy is admitted to Lakeshore Sentinel Hospital.

The idea for their guest appearance came about while Bush was promoting the series premiere of "Good Sam."

"People said, 'Would you want them to come on the show?' And I said, 'Of course.' And what a testament to my showrunner, Katie Welch. She said, 'Hey, I watched that interview you did today. There are these two women characters. Do you want Hilarie and (Bethany) Joy to come play them?'"

The trio also co-host a podcast called " Drama Queens " where they recap "One Tree Hill" episodes, speak with other actors from the show and reminisce about their time filming. Bush says it's "a rare opportunity to laugh a lot, have fun and to make fun of ourselves."

The memories are not all positive. In 2017, 18 female cast and crew members  penned a letter accusing former "One Tree Hill" showrunner Mark Schwahn of sexual harassment and manipulation. They address their experiences on "Drama Queens."

"We wanted to reclaim our show as women in a healthy way, to talk about what was good, what was bad, what we did well, what we could have done better," said Bush. "We knew it would be beautiful, but we didn't know we would feel so much healing, So we're really, really grateful."

Bush adds that some of what they rehash is edited out.

"Not everything is fit for public consumption, but in terms of themes, experiences and what we went through as young women, the ways we were not protected on our set, not fostered, not looked out for, we want to be really honest and for young women to know what it looks like."

On "Good Sam," Bush portrays a character who is experiencing her own power struggle, but with her father, played by Jason Isaacs. Bush's Sam took over her dad's role of chief of surgery when he was ill and he now wants his job back.

As a child, Bush wanted to be a surgeon so she has a real appreciation for medicine — including its terminology and instruments, which she says require "a lot of practice" to look natural holding.

"I have all sorts of surgical tools in my bag at all times that I'm just messing around with and doing finger work with pretty constantly. I have to be really careful when I get on a plane. You know, not to take like Cooley (cardiovascular) scissors to the airport because that wouldn't go over well with TSA."